The term “virtualization” is used frequently, but especially in relation to the servers. Here are answers to some frequently asked questions.

What Is Server Virtualization?

Virtualization is a term often applied to a wide range of technologies. In essence, virtualization technology means the use of distributed software hardware. In the area of server virtualization,  it means that some servers (Windows, Linux, etc.) can be placed on the same physical hardware. Thus, the two Linux-and Windows-based servers running on three machines can be virtualized and made to work on one server.

What Is A Virtual Machine?

Virtual Machine: The term is used for server environments running on the same hardware. Thus, in the example above, the division of Linux and Windows-based servers running on one physical server, is due to the virtual machine – special software that separates the hardware resources.

How Does Virtualization Works?

Typically, server virtualization separates the physical server resources. The physical disk is divided into parts that use different virtual servers. Computing resources are treated as the primary server resource pool, which can then be shared between virtual machines. Except for the sharing of computing resources, each virtual server acts as a single machine, the problems associated with operating software on one server does not affect other virtual machines on the same physical server.

What Are The Benefits Of Virtualization?

Benefits of properly designed and implemented virtualization are enormous.

Server Consolidation: The most frequently voiced advantage of virtualization. If applications running on different computers do not use all the computing resources of their computers, they can be combined onto fewer servers through virtualization technology. Usually used on physical servers that only uses 20 percent of computing power, and using virtualization server environments, you can improve hardware utilization upto 60 – 80 percent. Consolidation ratio is obtained by 3:1 or 4:1.

Minimization of the occupied space: Server virtualization reduces the number of physical servers that the company should use. This means that you can use a smaller data center, and, consequently, reduce the cost of cooling and electricity.

Decrease in value of equipment: Since virtualization allows for more efficient use of available resources, require fewer physical servers, resulting in savings of money spent on equipment and its contents.

Flexibility and speed: Because virtualization allows you to quickly create a variety of operating environments, it becomes easy to launch new version of the application to carry out transfer applications in the new environment, as well as to restore the system after the collapse.

Easy testing and development: Virtualization accelerates the development and testing, as easy deployment across operating systems. Virtualization allows developers to compare the performance of applications in various operating environments, and test applications in virtual environments (thus avoiding the destabilization of “working” system, which users can use during the test).

Which Issues Should Be Taken Seriously?

Cost of software / Licensing : One of the biggest problems, which must not be forgotten. Virtualization allows you to easily create new servers, and each of these server environments require a separate license for the software. If you are using the open-source, it will not be a problem, but if you run a paid environment, their deployment could lead to higher license fees.

The effectiveness of planning: In order to realize the full benefits of virtualization, it is important to match the hardware capabilities of the server with their requirements. In practice, this amounts to setting the maximum number of virtual servers on a physical server without degrading the performance of these servers.

Education: As with any change, the introduction of virtualization in the IT-environment will require training. Must take the costs (both time and money) into account.

Management: Despite the fact that the use of virtual servers reduces the amount of physical hardware, virtual machines require management.

High expectations from consolidation: Consolidation ratio depends on two things: the power of the current physical servers and resource requirements of existing applications. If existing servers have sufficient capacity, and your applications use them rationally, we can expect a high rate of consolidation. Conversely, if your server is not as powerful, but your applications use so much of the resources, do not expect the high rate of consolidation.

The increasing amount of investment: This is a potential problem. To realize the full benefits of virtualization, virtual machines must be located on a server with powerful processors. Less powerful hardware reduces the benefits of virtualization. There should be a compromise between the cost of new equipment and reduce the funding of the less powerful computers.

Unavailability of some systems: Especially in areas such as security, some systems are still not adapted to the peculiarities of virtualization. Many firewalls, for example, continue to believe that an IP-address corresponds to a single unit.

What Is The Difference Between Migration From Physical Server Hosting To Virtual?

Not such a big difference. Despite the fact that there are differences between operating systems, etc., the migration of a physical server into virtual entails the same consequences as the migration from one physical server to another.

What operating systems run on virtual servers?

It depends on the individual virtualization solutions, but almost all of the virtual systems work with Windows, Unix and Linux operating systems.

What Virtualization Tools Are Most Common?

So far dominated by VMware and controls 55 percent of virtual servers. Next comes the IBM (9,8 percent of the market). In the back of them breathes Microsoft, and it is quite possible that soon overtake due to the growing popularity of Hyper-V. Among other market participants, it should be noted SWsoft and Xen, respectively, with 6 and 3 percent of the market. Data, IDC.

How Many Virtual Machines Can One Server Run?

Number of virtual machines that can be deployed on the server, depending on server capacity (memory, processor speed, etc.) and application resource requirements for the virtual server. The higher capacity equipment and lower their consumption, the greater the number of virtual machines can be placed.

Conversely, a small capacity and high consumption of resources means that a smaller number of virtual machines can be placed on a single physical server.

There are many reasons why companies and organizations are investing in server virtualization. Some reasons are financially motivated, while the other roots lie in the technical plane.

Server virtualization helps by pooling to save space. The usual practice is to allocate a single dedicated server for each application. If multiple applications use only a small fraction of computing power, network administrator can combine multiple machines in a server with many virtual environments. The companies that have hundreds or thousands of servers at their disposal, such a merger could significantly reduce the need for physical space to host servers.

With virtualization, companies are able to make better use of reservation, without buying additional equipment. Reservation – a way of organizing, in which the same application running on multiple servers. This approach is dictated by security considerations – if for any reason, who will deny the server, it will replace another server that is running the same application. This allows us to minimize possible interruptions in service provision. It would be pointless to create two virtual servers with the same application on the same physical server. If there is an accident on this physical server, both of these virtual servers also stop working. In most cases, network administrators create backup on virtual servers or different physical machines.

Virtual servers provide programmers isolated independent systems, in which they can test new applications or operating systems. Instead of buying special physical machine network administrator can create a virtual server on an existing machine. Because each virtual server is independent in relation to all other servers, programmers can run programs on it without fear of harm to other applications.

In the end server hardware is obsolete, but switching from one system to another can be difficult. To these older systems, which are sometimes called legacy systems, were able to continue providing services, the network administrator can create a modern version of the old virtual server hardware. From an application perspective nothing has changed. The program functions as if they had continued to work on older hardware. Through this, company can get the time needed to transition to new processes without worrying that the equipment fails, especially in those cases when they released the inherited equipment company no longer exists and therefore cannot fix broken things.

There is a growing trend to shift to virtualization called migration. Migration – a transfer of the server environment from one place to another. With access to the appropriate hardware and software, you can move a virtual server from one physical machine to another network. Initially, this was only possible if both physical machines used the same operating systems, processors and other equipment. At present, migration of virtual servers on one physical machine to another is possible even when the machines are with different processors, it is necessary that they are made by one manufacturer.

Server computers - machines that store files and applications of computer networks – have to be very powerful. Some contain central processing units (CPU), consisting in turn of multiple processors, allowing them to easily perform complex tasks. Administrators of computer servers usually assign a separate server for a specific application or a specific task. Many problems cannot be well carried out jointly with others – each needs its own dedicated machine. Organization system of “one application – one server” also makes it easier to find the source of problems, if any. This approach, from a technical point of view is a simple way of ordering a computer network.

But this way of rationalizing raises a number of problems. One of them is that you do not use the full computing power of today’s server computers. Most dedicated servers use only a small fraction of their potential for information processing. Another problem is the need to allocate significant physical space to accommodate servers with increasing and more complex computer network. Ultimately, the data center can be crowded rack, basking and consuming large amounts of electricity.

Server virtualization is an attempt to simultaneously solve these two problems. Under the proposed method, an administrator, using special software that can convert a physical server into multiple virtual machines. Each virtual server acts as a separate physical device with its operating system (OS). Theoretically, you can create a sufficient number of virtual servers to use all the computing power of the machine, but in practice this approach is not always justified.

The concept of virtualization is not new. Computer scientists for decades have been creating virtual machines to supercomputers. However, only in recent years, the opportunity to implement server virtualization has came up. In a world of information technology (IT) server virtualization is a hot topic. This is still a new technology and several companies offer different approaches to its implementation.